Cooling Tower Water Balance — online
Evaporation, drift, blowdown, makeup and water cost for open recirculating towers — three cases side by side.
Yellow cells are inputs; orange cells are choices; blue cells choose the unit. Select or hover over an input to see its help in the box below the toolbar. The sheet is the same as the Excel tool (USD 29) — the Guide, method and references are in the Excel file.
What this cooling tower water balance calculator does
Know exactly where your cooling water goes, and what it costs. Evaporation, drift, blowdown, makeup and water cost for open recirculating towers — three cases side by side.
- Complete water balance. Evaporation, drift, blowdown and makeup, plus heat load, approach and effectiveness.
- Cycles three ways. Enter cycles directly, work them out from a water analysis (conductivity, chloride, silica, hardness or TDS), or from measured blowdown.
- Your choice of method. Evaporation factor from Perry, Marley or GPSA/Branan, or your own; blowdown with or without drift credited.
- Annual cost and savings. Water and blowdown treatment cost per year, and a what-if table for higher cycles.
- Field check. Compare the calculation with a site test using makeup, blowdown and basin level — find unaccounted losses and your tower's real evaporation factor.
- Three cases side by side. Design, actual and proposed, in any mix of SI, US and British units.
What you enter
- Blowdown basis
- Evaporation factor
- Custom evaporation factor
- Temperature input
- Cycles of concentration
- Analysis parameter
- What-if table based on
- Circulating water flow
- Cooling range, ΔT (hot − cold)
- Hot water temperature (to tower)
- Cold water temperature (from basin)
- Ambient wet-bulb (optional, for approach)
- Drift / windage loss
- Makeup water analysis
What you get
- Cooling range used
- Approach (cold water − wet-bulb)
- Heat load
- Cycles of concentration used
- Evaporation loss
- Total blowdown incl. drift
- Planned blowdown (to drain)
- Makeup water required
- Makeup as % of circulation
- Maximum achievable cycles (drift limit)
- Annual makeup volume
- Annual planned blowdown volume
- Annual makeup water cost
- Annual blowdown treatment cost
Related
- Free quick calculator — a simpler free version for a fast estimate.
- Calculation guide — the equations behind this tool, with a worked example.
- Cooling Tower Water Balance Excel tool — USD 29, keep the workbook and its Guide.
- All 40 online tools
Questions
Is the cooling tower water balance calculator free?
You can enter and check all your data free. The full results, findings and printable sheet are unlocked with a 3-run pack (USD 9), a monthly subscription to all 40 online tools (USD 15) or a yearly one (USD 99).
Are the results the same as the Excel tool?
Yes. The online tool runs the formulas of the Cooling Tower Water Balance Excel workbook, checked cell by cell against the Excel file.
Which units can I use?
SI, US customary and British units — choose the unit next to each input.